Comment 2 for bug 1674077

Hi Ignacio,
thank you for your report and your help to make Ubuntu better.
The logs that were attached did not lead me to an obvious error, mostly those issues are caused by incomplete or broken configurations. On package updates or reinstalls without former purging this config then makes the (re)start fail and cause an issue like the one you are facing.

If you happen to have no custom nginx config at all yet consider purging and reinstalling.
If you have a custom config consider disabling it for the upgrade and then step by step enable your config bits to find what breaks it.